Vehicle control apparatus

Abstract

A vehicle control apparatus is configured to execute processing to calculate a correction travel route and a control target value on the basis of a target travel route under a specified constraint condition. The vehicle control apparatus calculates the correction travel route by using an evaluation function in a manner to minimize a difference of the correction travel route from the target travel route. The evaluation function is a sum that is acquired by weighting the evaluation value at each prediction point by weight coefficients. A time interval between each adjacent pair of the prediction points is set to be increased from a near side toward a far side from the vehicle. The weight coefficients are set such that weight at the prediction point on the far side from the vehicle is less than the weight at the prediction point on the near side of the vehicle.

The invention claimed is: 
     
       1. A vehicle control apparatus for assisting with driving of a vehicle, wherein the vehicle control apparatus comprises:
 non-transitory computer-readable memory of an electronic control unit (ECU) of the vehicle control apparatus; and 
 a processor of the electronic control unit of the vehicle control apparatus operatively coupled to the non-transitory computer-readable memory and a plurality of sensors of the vehicle to receive sensor information from the sensors, the processor being configured to repeatedly execute, in specified control cycles:
 processing to calculate a target travel route of the vehicle; 
 processing to calculate a correction travel route based on the target travel route under a specified constraint condition using a vehicle model for estimation of behavior of the vehicle and to calculate a control target value of the vehicle so as to make the vehicle travel on the correction travel route; and 
 generate and output request signals to driving control components of the vehicle based on the control target value of the vehicle to make the vehicle travel on the correction travel route, wherein 
 
 when calculating the correction travel route, the vehicle control apparatus calculates the correction travel route using an evaluation function for evaluation of the correction travel route under the constraint condition to minimize a difference in the correction travel route from the target travel route, 
 the correction travel route includes plural prediction points that the vehicle passes before lapse of a specified prediction period, and the evaluation function is a sum that is acquired by weighting an evaluation value at each of the prediction points by a weight coefficient that is set for each of the prediction points, and 
 a time interval between each adjacent pair of the prediction points of the plural prediction points is set to be increased from a near side toward a far side from the vehicle, and the weight coefficient, which is set for each of the prediction points, is set such that weight at the prediction point on the far side from the vehicle is less than weight at the prediction point on the near side of the vehicle. 
 
     
     
       2. The vehicle control apparatus according to  claim 1 , wherein the weight at each of the prediction points is set to be inversely proportional to a square of a time that is required for the vehicle to arrive at each of the prediction points using the weight coefficient that is set for each of the prediction points. 
     
     
       3. The vehicle control apparatus according to  claim 2 , wherein
 at each of the prediction points, the evaluation function includes: an evaluation term to evaluate the correction travel route; and a constraint term that lowers the evaluation value when the correction travel route does not satisfy the constraint condition, 
 at each of the prediction points, weight of the weight coefficient of the constraint term is set to be greater than weight of the weight coefficient of the evaluation term, and the weight coefficient of the constraint term is set such that the weight thereof at the prediction point on the far side from the vehicle is less than the weight thereof at the prediction point on the near side of the vehicle. 
 
     
     
       4. The vehicle control apparatus according to  claim 3 , wherein
 the vehicle control apparatus detects an obstacle on outside of the vehicle, and sets a speed distribution area, which defines distribution of an allowable upper limit value of a relative speed of the vehicle to the obstacle, between the obstacle and the vehicle, and the allowable upper limit value in the speed distribution area is set to be increased as a distance from the obstacle is increased, and 
 the constraint condition includes that a relative speed of the vehicle to the obstacle does not exceed an allowable upper limit value in the speed distribution area. 
 
     
     
       5. The vehicle control apparatus according to  claim 3 , wherein
 the evaluation term has a plurality of evaluation factors, 
 the evaluation factors are set so as to respectively correspond to a plurality of physical amounts each representing a behavior of the vehicle at a correction target position, and 
 each of the physical amounts is one of a speed, acceleration, jerk, yaw rate, a lateral position with respect to a center of a lane, a vehicle angle, a steering angle, or a steering angular velocity of the vehicle. 
 
     
     
       6. The vehicle control apparatus according to  claim 1 , wherein the weight at each of the prediction points is set to be proportional to a common logarithm of a value that is inversely proportional to a square of a time required for the vehicle to arrive at each of the prediction points using the weight coefficient that is set for each of the prediction points. 
     
     
       7. The vehicle control apparatus according to  claim 6 , wherein
 at each of the prediction points, the evaluation function includes: an evaluation term to evaluate the correction travel route; and a constraint term that lowers the evaluation value when the correction travel route does not satisfy the constraint condition, 
 at each of the prediction points, weight of the weight coefficient of the constraint term is set to be greater than weight of the weight coefficient of the evaluation term, and the weight coefficient of the constraint term is set such that the weight thereof at the prediction point on the far side from the vehicle is less than the weight thereof at the prediction point on the near side of the vehicle. 
 
     
     
       8. The vehicle control apparatus according to  claim 7 , wherein
 the vehicle control apparatus detects an obstacle on outside of the vehicle, and sets a speed distribution area, which defines distribution of an allowable upper limit value of a relative speed of the vehicle to the obstacle, between the obstacle and the vehicle, and the allowable upper limit value in the speed distribution area is set to be increased as a distance from the obstacle is increased, and 
 the constraint condition includes that a relative speed of the vehicle to the obstacle does not exceed an allowable upper limit value in the speed distribution area. 
 
     
     
       9. The vehicle control apparatus according to  claim 8 , wherein
 the evaluation term has a plurality of evaluation factors, 
 the evaluation factors are set so as to respectively correspond to a plurality of physical amounts each representing a behavior of the vehicle at a correction target position, and 
 each of the physical amounts is one of a speed, acceleration, jerk, yaw rate, a lateral position with respect to a center of a lane, a vehicle angle, a steering angle, or a steering angular velocity of the vehicle. 
 
     
     
       10. The vehicle control apparatus according to  claim 7 , wherein
 the evaluation term has a plurality of evaluation factors, 
 the evaluation factors are set so as to respectively correspond to a plurality of physical amounts each representing a behavior of the vehicle at a correction target position, and 
 each of the physical amounts is one of a speed, acceleration, jerk, yaw rate, a lateral position with respect to a center of a lane, a vehicle angle, a steering angle, or a steering angular velocity of the vehicle. 
 
     
     
       11. The vehicle control apparatus according to  claim 4 , wherein
 the evaluation term has a plurality of evaluation factors, 
 the evaluation factors are set so as to respectively correspond to a plurality of physical amounts each representing a behavior of the vehicle at a correction target position, and 
 each of the physical amounts is one of a speed, acceleration, jerk, yaw rate, a lateral position with respect to a center of a lane, a vehicle angle, a steering angle, or a steering angular velocity of the vehicle. 
 
     
     
       12. The vehicle control apparatus according to  claim 1 , wherein
 at each of the prediction points, the evaluation function includes: an evaluation term to evaluate the correction travel route; and a constraint term that lowers the evaluation value when the correction travel route does not satisfy the constraint condition, 
 at each of the prediction points, weight of the weight coefficient of the constraint term is set to be greater than weight of the weight coefficient of the evaluation term, and the weight coefficient of the constraint term is set such that the weight thereof at the prediction point on the far side from the vehicle is less than the weight thereof at the prediction point on the near side of the vehicle. 
 
     
     
       13. The vehicle control apparatus according to  claim 12 , wherein
 the vehicle control apparatus detects an obstacle on outside of the vehicle, and sets a speed distribution area, which defines distribution of an allowable upper limit value of a relative speed of the vehicle to the obstacle, between the obstacle and the vehicle, and the allowable upper limit value in the speed distribution area is set to be increased as a distance from the obstacle is increased, and 
 the constraint condition includes that a relative speed of the vehicle to the obstacle does not exceed an allowable upper limit value in the speed distribution area. 
 
     
     
       14. The vehicle control apparatus according to  claim 12 , wherein
 the evaluation term has a plurality of evaluation factors, 
 the evaluation factors are set so as to respectively correspond to a plurality of physical amounts each representing a behavior of the vehicle at a correction target position, and 
 each of the physical amounts is one of a speed, acceleration, jerk, yaw rate, a lateral position with respect to a center of a lane, a vehicle angle, a steering angle, or a steering angular velocity of the vehicle. 
 
     
     
       15. A vehicle control apparatus for assisting with driving of a vehicle, wherein the vehicle control apparatus is configured to repeatedly execute, in specified control cycles:
 processing to calculate a target travel route of the vehicle; and 
 processing to calculate a correction travel route based on the target travel route under a specified constraint condition using a vehicle model for estimation of behavior of the vehicle and to calculate a control target value of the vehicle so as to make the vehicle travel on the correction travel route, 
 when calculating the correction travel route, the vehicle control apparatus calculates the correction travel route using an evaluation function for evaluation of the correction travel route under the constraint condition to minimize a difference in the correction travel route from the target travel route, 
 the correction travel route includes plural prediction points that the vehicle passes before lapse of a specified prediction period, and the evaluation function is a sum that is acquired by weighting an evaluation value at each of the prediction points by a weight coefficient that is set for each of the prediction points, and 
 a time interval between each adjacent pair of the prediction points of the plural prediction points is set to be increased from a near side toward a far side from the vehicle, and the weight coefficient, which is set for each of the prediction points, is set such that weight at the prediction point on the far side from the vehicle is less than weight at the prediction point on the near side of the vehicle, 
 the vehicle control apparatus detects an obstacle on outside of the vehicle, and sets a speed distribution area, which defines distribution of an allowable upper limit value of a relative speed of the vehicle to the obstacle, between the obstacle and the vehicle, and the allowable upper limit value in the speed distribution area is set to be increased as a distance from the obstacle is increased, and 
 the constraint condition includes that a relative speed of the vehicle to the obstacle does not exceed an allowable upper limit value in the speed distribution area. 
 
     
     
       16. The vehicle control apparatus according to  claim 15 , wherein the weight at each of the prediction points is set to be proportional to a common logarithm of a value that is inversely proportional to a square of a time required for the vehicle to arrive at each of the prediction points using the weight coefficient that is set for each of the prediction points. 
     
     
       17. The vehicle control apparatus according to  claim 16 , wherein
 at each of the prediction points, the evaluation function includes: an evaluation term to evaluate the correction travel route; and a constraint term that lowers the evaluation value when the correction travel route does not satisfy the constraint condition, 
 at each of the prediction points, weight of the weight coefficient of the constraint term is set to be greater than weight of the weight coefficient of the evaluation term, and the weight coefficient of the constraint term is set such that the weight thereof at the prediction point on the far side from the vehicle is less than the weight thereof at the prediction point on the near side of the vehicle.